[Stock Helicopters & Turboprops] Non DLC Will Always Be More Fun!

[Gman_builder]

If you check out some of @erasmusguy's older engines on KerbalX you'll see that he made some really smooth gear mesh's and very smoothly operating turboshafts. I would consult with him about the building of a transmission or a gearbox if he was active on this thread. https://kerbalx.com/erasmusguy/undefined 

I think up-gearing engines might be the most efficient method of either driving land based vehicles or possibly making realistic turboprops to fly aircraft. That way you could(theoretically) take a much smaller, less gas guzzling, lower part count, less glitchy engine and have it perform similarly to that of our massive 70+ blower engines. Possibly working in tandem as well for a twin engines design.

[Pds314]

2 minutes ago, Gman_builder said:

If you check out some of @erasmusguy's older engines on KerbalX you'll see that he made some really smooth gear mesh's and very smoothly operating turboshafts. I would consult with him about the building of a transmission or a gearbox if he was active on this thread. https://kerbalx.com/erasmusguy/undefined 

I think up-gearing engines might be the most efficient method of either driving land based vehicles or possibly making realistic turboprops to fly aircraft. That way you could(theoretically) take a much smaller, less gas guzzling, lower part count, less glitchy engine and have it perform similarly to that of our massive 70+ blower engines. Possibly working in tandem as well for a twin engines design.

Well, you've still gotta design an engine that can survive high RPM. It's the difference between 70 blowers and 40 or so unless you can make crazy fast engines.

[Gman_builder]

3 minutes ago, Pds314 said:

Well, you've still gotta design an engine that can survive high RPM. It's the difference between 70 blowers and 40 or so unless you can make crazy fast engines.

I mean, you can take a engine that has a low operating speed, like 30ish rad/s. Then up-gear it so the prop spins at around 50 rad/s or higher,

[Pds314]

1 minute ago, Gman_builder said:

I mean, you can take a engine that has a low operating speed, like 30ish rad/s. Then up-gear it so the prop spins at around 50 rad/s or higher,

I think that's the opposite of what we want. LOL. I already have engines that can turn a shaft at 70 forever. I need a way to convert >50 rad/s engine down to <50 speeds and high torque.

[Gman_builder]

Then you would have to have either LOTS of gears in the transmission for minimal torque on the engine, like real turboprop gearboxes, or produce an engine that has high torque while remaining in the design parameters that benefit from having a gearbox design instead of linking the engine directly to the prop.

[Pds314]

4 minutes ago, Gman_builder said:

Then you would have to have either LOTS of gears in the transmission for minimal torque on the engine, like real turboprop gearboxes, or produce an engine that has high torque while remaining in the design parameters that benefit from having a gearbox design instead of linking the engine directly to the prop.

Well I really can't see any benefit to gearing up a perfectly good engine. It means you need more torque, i.e. More blowers, to operate at the same speed.


Here:

100 kN*m engine at 80 rads/s geared down to 40 is 200 kN*m at 40 rads/s.

100 kN*m engine at 20 geared up to 40 is 50 kN*m at 40 rads/s.

Same engine. Same weight. 1/4th the power, torque and efficiency.

Edited July 21, 2016 by Pds314

[Gman_builder]

6 minutes ago, Pds314 said:

Well I really can't see any benefit to gearing up a perfectly good engine. It means you need more torque, i.e. More blowers, to operate at the same speed.


Here:

100 kN*m engine at 80 rads/s geared down to 40 is 200 kN*m at 40 rads/s.

100 kN*m engine at 20 geared up to 40 is 50 kN*m at 40 rads/s.

Same engine. Same weight. 1/4th the power, torque and efficiency.

I'm saying you take a engine that doesn't produce enough power to lift a aircraft. And you UP-GEAR IT. So you have the efficiency of a engine with few blowers and the additional power from increasing the prop RPM through gearing.

But whatever its just an idea. I think it's more applicable in cars and other land vehicles that are slow as fook right now like my turboshaft cars. My 2 wheel drive car managed about 15 m/s I think which was plenty for safe operating but my 4 wheel drive model with a similar powerplant did 4 m/s

 

[Pds314]

9 minutes ago, Gman_builder said:

I'm saying you take a engine that doesn't produce enough power to lift a aircraft. And you UP-GEAR IT. So you have the efficiency of a engine with few blowers and the additional power from increasing the prop RPM through gearing.

But you're decreasing the engine RPM, making the engine less efficient. It isn't the prop that has constant torque but variable RPM. It's the engine.

Having a low-RPM engine spin a high-RPM prop means the engine loses torque. Having a high-RPM engine spin a low-RPM prop means the engine gains torque. That's why 1st gear in a car is geared down for torque and last gear is geared up to increase RPM.

Somewhat worthy of note is that if anyone builds a car for speed, they'll have to contend with this the other direction, as the engine has a max RPM that can be exceeded, possibly before the max RPM of the wheels.

In any case, props cannot sustain 52 rads/s or better. Period. Engines are known to be able to sustain at least 80. The only way to increase prop performance beyond that point is to increase pitch, or if pitch is stalled, increase number or diameter of blades.

Edited July 22, 2016 by Pds314

[Gman_builder]

1 minute ago, Pds314 said:

But you're decreasing the engine RPM, making the engine less efficient. It isn't the prop that has constant torque but variable RPM. It's the engine.

Having a low-RPM engine spin a high-RPM prop means the engine loses torque. Having a high-RPM engine spin a low-RPM prop means the engine gains torque. That's why 1st gear in a car is geared down for torque and last gear is geared up to increase RPM.

Somewhat worthy of note is that if anyone builds a car for speed, they'll have to contend with this the other direction, as the engine has a max RPM that can be exceeded, possibly before the max RPM of the wheels.

In any case, props cannot sustain 52 rads/s or better. Period. Engines are known to be able to sustain at least 80.

Hmm. ya I was thinking about it backwards. whoops. But still the best way to transfer power through a driveline with minimal lag and fuel consumption would be linking a single engine to a geared transmission similar to the one in my 4 wheel drive car. I am thinking about going back and changing some gear sizes to hopefully increase speed.

[Pds314]

5 minutes ago, Gman_builder said:

Hmm. ya I was thinking about it backwards. whoops. But still the best way to transfer power through a driveline with minimal lag and fuel consumption would be linking a single engine to a geared transmission similar to the one in my 4 wheel drive car. I am thinking about going back and changing some gear sizes to hopefully increase speed.

Yeah. Well basically, it's the acceleration vs. top speed game. If you want better acceleration and efficiency, you need the engine geared down. If you want a higher max speed, you need the engine geared up. Note that this only applies if your wheels can take more angular velocity than your engine, which is probably manifestly untrue in your case.

Edited July 22, 2016 by Pds314

[Gman_builder]

Just now, Pds314 said:

Yeah. Well basically, it's the acceleration vs. top speed game. If you want better acceleration and efficiency, you need the engine geared down. If you want a higher max speed, you need the engine geared up. Note that this only applies if your wheels can take more angular velocity than your engine, which is probably manifestly untrue in your case.

Ya the problem with gears running at high speed in this game is that each tooth collides with the tooth in the other gear at very high velocities, so that limits what you can build them out of to structural panels and I-Beams. but even still, your at risk of breaking the gears. So I am hoping to achieve around 25 m/s out of a 2 wheel drive car, because it's impossible to steer a 4 wheel drive car. I would have to develop a stock steering system. So ya, 25 m/s isn't very fast so hopefully you wouldn't be breaking any parts and it's still fast enough to get where you need to go quickly enough. Then you could just have landing gear up front to do the steering which is what I had originally.

[Pds314]

2 minutes ago, Gman_builder said:

Ya the problem with gears running at high speed in this game is that each tooth collides with the tooth in the other gear at very high velocities, so that limits what you can build them out of to structural panels and I-Beams. but even still, your at risk of breaking the gears. So I am hoping to achieve around 25 m/s out of a 2 wheel drive car, because it's impossible to steer a 4 wheel drive car. I would have to develop a stock steering system. So ya, 25 m/s isn't very fast so hopefully you wouldn't be breaking any parts and it's still fast enough to get where you need to go quickly enough. Then you could just have landing gear up front to do the steering which is what I had originally.

That's what my useless tractor has.

[Gman_builder]

Just now, Pds314 said:

That's what my useless tractor has.

front wheel steering? Or no steering at all?

[Pds314]

Just now, Gman_builder said:

front wheel steering? Or no steering at all?

Landing gears. Problem is that they are much grippier than the wheels.

[Gman_builder]

Just now, Pds314 said:

Landing gears. Problem is that they are much grippier than the wheels.

For my main wheels I used fairing disks surrounded by small landing gear with the brakes on for traction. That worked exceptionally well.

[Pds314]

1 minute ago, Gman_builder said:

For my main wheels I used fairing disks surrounded by small landing gear with the brakes on for traction. That worked exceptionally well.

Yeah. I think physicsless structural parts might not be good tires. =/

[Gman_builder]

Just now, Pds314 said:

Yeah. I think physicsless structural parts might not be good tires. =/

Lol yeah

You can download my cars her and try them out for yourself

4 wheel drive car: https://kerbalx.com/Gman_builder/Gremlin-MK1

2 wheel drive car: https://kerbalx.com/Gman_builder/Stock-turboshaft-car

To drive them you must engage the brakes BEFORE you stage. Otherwise you will have no traction.

[Pds314]

I'm having some success an internal-external configuaration of gears. Specifically, I got an engine at 70 rads/s to somewhat stably run a shaft at 35 rads/s geared down by 4/8 reduction gear. I'm now having similar success with a 4/24 reduction gear reducing 70 rads/s down to 11.5 or so.

[Gman_builder]

43 minutes ago, Pds314 said:

I'm having some success an internal-external configuaration of gears. Specifically, I got an engine at 70 rads/s to somewhat stably run a shaft at 35 rads/s geared down by 4/8 reduction gear. I'm now having similar success with a 4/24 reduction gear reducing 70 rads/s down to 11.5 or so.

I am not really sure what all those numbers mean because I have no reference point. But it sounds like your making progress, so keep it up I guess.

[Pds314]

22 minutes ago, Gman_builder said:

I am not really sure what all those numbers mean because I have no reference point. But it sounds like your making progress, so keep it up I guess.

I successfully modified a really mindblowingly fast engine's torque to be slow but exceedingly strong. Changing about 40 or 50 kN*m at 70 rads/s to about 240-300 at 11.5 rads/s. The big issue is it involves a massive 24-tooth physicsless gear. That's not a problem for making, say, a huge Varpulis-powered vehicle with millions of Newton-meters of torque and the ability to spin helicopter rotors the size of a small city, but it's not so good for making practical car engines.

Edited July 22, 2016 by Pds314

[Gman_builder]

14 minutes ago, Pds314 said:

I successfully modified a really mindblowingly fast engine's torque to be slow but exceedingly strong. Changing about 40 or 50 kN*m at 70 rads/s to about 240-300 at 11.5 rads/s. The big issue is it involves a massive 24-tooth physicsless gear. That's not a problem for making, say, a huge Varpulis-powered vehicle with millions of Newton-meters of torque and the ability to spin helicopter rotors the size of a small city, but it's not so good for making practical car engines.

Alrighty, so what are you going to do with this new-found info and technology?

Will he build a car.....

Will he built a plane.....

Will he build a helicopter.....

The world may never know.....

 

I have been working on a silly little engine for about a month now I call the G-47-4F.  It makes 45 rad/s in a 1.8 meter diameter form factor(excluding prop). I was planning on using it for my endurance challenge for it's inherent efficiency(only 24 Juno's) but I might move the project over to the "Land vehicle Division" of my crazy KSP laboratory. I will be able to create much smaller and hopefully faster cars with the new engine.

 

I also had an genius idea for a super simple stock gear shifter. More on that later.

[Pds314]

Maybe I shall make a wheel-driven racer, define a track, and run a time trial. =)

 

On the other hand, maybe I'd be better off making a more practical gearing system first.

Edited July 22, 2016 by Pds314

[Pds314]

Wait wait wait... I just realized...

 

 

Could work without meshing problems.

[Gman_builder]

51 minutes ago, Pds314 said:

Wait wait wait... I just realized...

 

 

Could work without meshing problems.

Is that supposed to mean something to me? What is it?

Edited July 22, 2016 by Gman_builder

[Azimech]

5 hours ago, Gman_builder said:

Is that supposed to mean something to me? What is it?

It's a concept for changing a rotational motion from one plane to another.